1. Field of the Invention
The present invention relates generally to manhole lining techniques, and more particularly to a pipe liner bag everting nozzle and a pipe lining method using the same.
2. Description of the Related Art
When an underground pipe, such as pipelines and passageways, becomes defective or too old to perform properly, the pipe is repaired and rehabilitated without digging the earth to expose the pipe and disassembling the sections of the pipe. This non-digging method of repairing an underground pipe has been known and practiced commonly in the field of civil engineering. The pipe lining method utilizes a tubular pipe liner bag made of a resin absorbent material impregnated with a hardenable resin, and having the outer surface covered with a highly air-tight plastic film. The tubular pipe liner bag is inserted into a pipe to be repaired by means of a pressurized fluid such that the pipe liner bag is turned inside out as it proceeds deeper in the pipe. Hereinafter, this manner of insertion shall be called “everting”. When the entire length of the tubular liner bag is everted (i.e., turned inside out) into the pipe, the everted tubular liner is pressed against the inner wall of the pipe by a pressurized fluid, and the tubular flexible liner is hardened as the hardenable resin impregnated in the liner is heated, which is effected by heating the fluid filling the tubular liner bag. It is thus possible to line the inner wall of the defective or old pipe with a rigid liner without digging the ground and disassembling the pipe sections.
Specifically, in the foregoing pipe lining method, one end of a pipe liner bag 201 is folded out, for example, as illustrated in FIG. 30, and a folded portion of the pipe liner bag 201 is fixed over the outer periphery of an upper end of a top collar 202 installed on the ground. Then, water is poured into the folded portion of the pipe liner bag 201 from a water supply hose 203 to evert the pipe liner bag 201 with the water pressure. Consequently, the pipe liner bag 201 is inserted into a pipe line 250 through a manhole 251.
However, the conventional pipe lining method illustrated in FIG. 30 involves passage of the pipe liner bag 201, which has a diameter substantially equal to the inner diameter of the pipe line 250, through the manhole 251, the opening of the manhole 251 is almost closed by the pipe liner bag 201 particularly when the pipe line 251 has a large diameter, so that an operator cannot enter the manhole 251 for inspection or the like during the lining operation. Also, the pipe liner bag 201 inevitably includes a portion which does not serve for lining the pipe line 250 (a portion of the pipe liner bag 201 which extends from the pipe line 250 to the ground through the manhole 251), and this portion is wasted, thus causing a problem from an economical point of view.
To solve this problem, a method of installing a cylindrical pipe liner bag everting nozzle 204 on the bottom of the manhole 251, as illustrated in FIG. 31, has been proposed in view of economies. Specifically, the illustrated method involves inserting a guide tube 206, having one end attached to a top collar 205 installed on the ground, into the manhole 251; fixing the other end of the guide tube 206 to a guide tube fixing end which is open to one end of the pipe liner bag everting nozzle 204; passing a pipe liner bag 201 into the guide tube 206 and the pipe liner bag everting nozzle 204 from the ground; folding out a leading end portion of the pipe liner bag 201 and fixing the folded portion to a pipe liner bag fixing end which is open to the other end of the pipe liner bag everting nozzle 304; pouring water into the folded portion of the pipe liner bag 201 from a water supply hose 203 to evert the pipe liner bag 201 into a pipe line 250 with the water pressure.
However, even in the foregoing improved method, the guide tube fixing end of the pipe liner bag everting nozzle 204 has the same diameter as the pipe liner bag fixing end, so that the guide tube 206 having a larger diameter is required as the pipe line 250 is larger. Therefore, as illustrated in FIG. 31, the opening of the manhole 251 is almost closed by the guide tube 206, thereby preventing the operator from entering the manhole 251 for inspection or the like during the lining operation.
In addition, when the pipe liner bag 201 is everted using an elbow-shaped pipe liner bag everting nozzle 207 which is bent at 90 degrees as illustrated in FIG. 32, the pipe liner bag everting nozzle 207 has a larger height dimension H. For passing the pipe liner bag everting nozzle 207 through the opening of the manhole 251, the height dimension H must be smaller than the opening diameter D of the manhole 251 (H<D). Also, a diameter d of the pipe liner bag fixing end of the pipe liner bag everting nozzle 207 is limited by the height dimension H, applications of this type of pipe liner bag everting nozzle 207 are limited to pipe lines having small diameters.